This invention relates to a resilient coupling device for a double-twist twisting mechanism with two assemblies which rotate about adjacent non-concentric axes. A twisting mechanism of this type described in copending U.S. patent application Ser. No. 882,513, filed Mar. 1, 1978, the entirety of which is incorporated herein by reference.
Mechanisms of this type comprise a centered assembly which includes a rotational spindle and a spool holder, and an off-centered assembly which rotates about an axis which is oblique to the rotational axis of the centered assembly and is pivotally connected to the spool holder and to a stationary base or frame. These two assemblies are fitted one into the other, and they are coupled together by resilient means.
The resilient coupling means disclosed in the prior application is a polygonal ring of flexible elastomeric material, having pin-receiving openings at each corner. These openings fit over a certain number of pins. All of the pins project in the same direction, substantially at the same level and are fixed alternately in the centered assembly and in the off-centered assembly so as to enable this ring to be easily placed in position and removed. For this purpose, the distance between the axes of the various pins must be such that the perimeter of the polygonal ring is sufficient to enable the ring to pass around the members of the twisting mechanism. Each side of the polygonal ring forms an elastomeric tie bar, which is able to work only under tension so that during rotation it undergoes an overall elongation due to the centrifugal force acting on its mass. Also, alternating elongations lead to breakage of the ring, particularly in the area where it is connected to the pins.
It is an object of the present invention to overcome the aforesaid drawbacks by providing an improved resilient coupling means for a twisting mechanism of the above-mentioned type. The improved coupling means is less susceptible to breakage, has less mass affected by centrifugal force, and imposes no geometrical requirement on the spacing of the pins relative to the axis of the twister.